Membrane keyboards circuit

I study the different keyboard technologies and I have noticed that on membrane keyboards there are no diodes to prevent ghosting.
From what I understand:

The switch are placed in such a way that some combinations (the most useful) are possible without ghosting

On the other hand, there are some critical combinations, which cause ghosting.

To avoid ghosting of critical combinations, the firmware stops ghosting by not transmitting the ghost key

This is why many keyboards do not exceed 2KRO.

Can you confirm if I just? ^^

So I looked for open source projects of this type of membrane keyboard but I didn't find anything.
(Which doesn't surprise me, because there are a lot of disadvantages with membrane keyboards.)
But I still thought I would find a keyboard that would take this type of circuit without diodes.

So, do you know where I can find this type of circuit, a matrix of switch without diodes for keyboard?